Nikon is probably trying to bridge the gap between the prices of non-DSLR and DSLR camera models, giving new users a smaller and lighter dSLR at an attractive price.

All of the major manufacturers do that kind of thing to some extent, since they want to attract more new camera buyers, and also want to offer features in their more profitable camera models that give camera owners a reason to upgrade.

Nikon made out in more than one way with their newer D40 and D40x models. They left out features like a focus motor to make them less expensive and more attractive to new dSLR camera buyers, and also made more money on lenses (since new D40 and D40x owners don't have as many third party lens choices as D50 owners, because Nikon's newer entry level models require lenses with focus motors built in, which eliminated the vast majority of non-Nikon lenses that could be used with these camera models when they were introduced, if you wanted Autofocus).

Lens availability from third party manufacturers is improving though, as they are gearing up to offer more lenses with motors built in for D40/D40x/D60 owners (although Nikon sure caught them off guard using this tactic).

After all, Nikon is not doing this just for the fun of it. They want to make a profit selling cameras and lenses. ;-)